The present invention relates to a printing device which is installed in, for example, a photograph printer, and which prints an image on a photosensitive material by directing light from a light source on the photosensitive material through a light modulation element such as a liquid crystal display element, and also concerns a photograph processing apparatus equipped with such a printing device.
Conventionally, various printing devices have been proposed in which an image is displayed by a liquid crystal display element (hereinafter, referred to as LCD (Liquid Crystal Display) and light from a light source is directed to a photosensitive material through this LCD so as to print the image. In the printing device of this type, for example, a film image is acquired as image data consisting of a plurality of pixels, and pixels on the LCD are modulated in accordance with the image data thus acquired so that the photosensitive material is exposed.
In the above-mentioned conventional printing device, in the case when a color image is printed on a photosensitive material, color exposure is carried out based upon the so-called additive color process. In other words, the system which represents a color image by superposing light rays having blue (B), green (G) and red (R) components is adopted.
The following description will discuss a structural example of the conventional printing device. FIG. 7 is a perspective view that schematically shows the construction of the printing device which is provided with an LCD and carries out face exposure. Here, the printing device having such a construction is referred to as a printing device of one-head face exposure system.
This printing device of one-head face exposure system is provided with a light source 51 for emitting white light, a BGR filter 52 having filters corresponding to the respective colors of blue, green and red, an LCD 53 and a printing lens 54. Light, released from the light source 51, is made incident on the LCD 53 after passing through any of the filters of the respective colors in the BGR filter 52. The light, made incident on the LCD 53, is modulated by the LCD 53 that displays image information corresponding to a color at this time, and then directed onto printing paper 55 as a photosensitive material through the printing lens 54. An image as a whole to be printed is displayed on the LCD 53, and the image is printed on the printing paper 55 that is placed at rest.
As described above, in the printing device of the one-head face exposure system, color exposure is carried out by using the BGR filter 52. In other words, for example, when the filter corresponding to blue is being used, image information corresponding blue is displayed on the LCD 53 so that an exposing process of the blue component of the image is carried out on the printing paper 55, and the same exposing processes of the green and red components are then carried out in this order so as to print the color image.
FIG. 8 is a perspective view that schematically shows the construction of a printing device which is provided with light sources and LCDs that correspond to the respective colors of blue, green and red, and carries out face exposure. Here, the printing device having such a construction is referred to as a printing device of three-head face exposure system.
This printing device of three-head face exposure system is provided with three light sources 51B, 51G and 51R for respectively emitting blue light, green light and red light, three LCDs 53B, 53G and 53R, a composition prism 56 and a printing lens 54. Light rays, released from the light sources 51B, 53G and 53R, are made incident on the corresponding LCDs 53B, 53G and 53R, and modulated in accordance with image information for the respective colors. The resulting light rays, released from the LCDs 53B, 53G and 53R are composed by the composition prism 56, and projected onto printing paper 55 through the printing lens 54. An image as a whole to be printed is displayed on each of the LCDs 53B, 53G and 53R for each of the colors, and the image is printed on the printing paper 55 that is placed at rest.
As described above, in the printing device of the three-head face exposure system, the light sources 51B, 51G and 51R and the LCDs 53B, 53G and 53R are used for directing image light rays of the blue, green and red components to the composition prism 56 simultaneously so that an exposing process is carried out on the printing paper 55 by using color image light rays from the composition prism 56.
FIG. 9 is a perspective view that schematically shows the construction of a printing device which is provided with light sources and LCS""s (Liquid Crystal Shutters) that correspond to the respective colors of blue, green and red, and carries out scanning exposure by directing parallel light rays from the respective LCS""s onto printing paper. In this case, LCS refers to a liquid crystal element in which respective pixels are aligned in one row or in several rows. Here, the printing device having such a construction is referred to as a printing device of three-head parallel scanning exposure system.
This printing device of three-head parallel scanning exposure system is provided with three light sources 51B, 51G and 51R for respectively emitting blue light, green light and red light, three LCS""s 57B, 57G and 57R, and three rod lens arrays 58B, 58G and 58R. Light rays, released from the light sources 51B, 51G and 51R, are made incident on the corresponding LCS""s 57B, 57G and 57R, and modulated in accordance with image information for the respective colors. The resulting light rays, released from the LCS""s 57B, 57G and 57R are projected onto printing paper 55 through the respective rod lens arrays 58B, 58G and 58R. Image data corresponding to one row or several rows of an image to be printed is displayed on the LCS""s 57B, 57G and 57R for the respective colors, and scanning exposure is carried out by transporting the printing paper 55 in a direction orthogonal to the length direction of the respective LCS""s.
As described above, in the printing device of the three-head parallel scanning exposure system, the light sources 51B, 51G and 51R and the LCS""s 57B, 57G and 57R are used for directing image light rays of the blue, green and red components onto the printing paper 55 in parallel with each other. Then, the display timing of the LCS""s 57B, 57G and 57R is controlled based upon the relationship between the distance between irradiation positions of the respective colors and the transporting speed of the printing paper 55 so that a color exposing process is carried out on each of the respective pixels of the image to be printed.
FIG. 10 is a perspective view that schematically shows the construction of a printing device which is provided with light sources and LCS""s (Liquid Crystal Shutters) that correspond to the respective colors of blue, green and red, and carries out scanning exposure by directing light composed by light rays from the respective LCS""s onto printing paper. Here, the printing device having such a construction is referred to as a printing device of three-head composition scanning exposure system.
This printing device of three-head composition scanning exposure system is provided with three light sources 51B, 51G and 51R for respectively emitting blue light, green light and red light, three LCS""s 57B, 57G and 57R, a composition prism 56 and a rod lens arrays 58. Light rays, released from the light sources 51B, 51G and 51R, are made incident on the corresponding LCS""s 57B, 57G and 57R, and modulated in accordance with image information for the respective colors. The resulting light rays, released from the LCS""s 57B, 57G and 57R are composed by the composition prism 56, and projected onto printing paper 55 through the respective the rod lens array 58. Image data corresponding to one row or several rows of an image to be printed is displayed on the LCS""s 57B, 57G and 57R for the respective colors, and scanning exposure is carried out by transporting the printing paper 55 in a direction orthogonal to the length direction of the respective LCS""s.
As described above, in the printing device of the three-head composition scanning exposure system, the light sources 51B, 51G and 51R and the LCS""s 57B, 57G and 57R are used for directing image light rays of the blue, green and red components onto the composition prism 56 simultaneously, and the resulting color image light rays from the composition prism 56 are used for exposing the printing paper.
In the case of the printing device of one-head face exposure system as shown in FIG. 7, a color image is printed by carrying out serial exposing processes in the order of blue, green and red colors as described above. Therefore, as compared with the arrangement for carrying out exposing processes with the respective colors simultaneously, this system has a problem of low processability.
In the case of the printing device of three-head face exposure system as shown in FIG. 8, as described above, image light rays of the blue, green and red components are composed by using the composition prism 56, and the light rays corresponding to the respective colors are simultaneously directed onto the printing paper 55. In this manner, when the composition prism 56 is used, the aligning positions and aligning directions of the composition prism 56 and the LCDs 53B, 53G and 53R need to be set very accurately so as to keep an accurate positional relationship between the respective pixels representative of the respective color components of the image light rays; this causes an increase in production costs as well as manufacturing time. Moreover, the composition prism 56, which is a comparatively expensive member, also causes an increase in material costs.
In the printing device of three-head parallel scanning exposure system as shown in FIG. 9, as described above, a scanning exposure process is carried out while the image light rays of the blue, green and red components are directed to respectively different positions on the printing paper 55. In this arrangement, the image display timing of the LCS""s 57B, 57G and 57R has to be controlled precisely so that the respective color components of the pixels in an image to be printed on the printing paper 55 are accurately superposed on each other. In other words, data corresponding to the respective pixels need to be displayed in different timing for the respective color components; this makes the image controlling process more complex.
Moreover, the image display timing is set based upon the relationship between the gap of the light rays of the respective color components and the transporting speed of the printing paper 55; however, in the event of an error in these values, pixel offsets, which are caused by offset exposing light rays of the respective color components, tend to occur in the respective pixels. Moreover, in the case when the aligned position of the optical system is offset with respect to the image light rays of the respective color components, the above-mentioned pixel offsets tend to occur. In other words, the system of this type is highly susceptible to the occurrence of pixel offsets.
In the printing device of three-head composition scanning exposure system as shown in FIG. 10, as described above, the image light rays of the blue, green and red components are composed by the composition prism 56, and while simultaneously projecting the light rays of the three colors onto printing paper 55, scanning exposure is carried out. As described above, when the composition prism 56 of this type is used, the aligning positions and aligning directions of the composition prism 56 and the LCS""s 57B, 57G and 57R need to be set very accurately so as to keep an accurate positional relationship between the respective pixels representative of the respective color components of the image light rays; this causes an increase in production costs as well as manufacturing time. Moreover, the composition prism 56, which is a comparatively expensive member, also causes an increase in material costs.
The present invention relates to a printing device which prints a color image on a photosensitive material by modulating light from a light source for each pixel in accordance with image information, and its objective is to provide a superior printing device with high processability which is less susceptible to pixel offsets in the image printed on the photosensitive material by using a simple construction.
In order to achieve the above-mentioned objective, the printing device of the present invention is provided with:
a light source; and
an exposing means for modulating light from the light source for each pixel and for directing the resulting light to a photosensitive material, the exposing means being provided with a plurality of light modulating elements which control the transmission and interruption of light rays having respectively different specific wavelength bands and which transmit light rays having the other wavelength bands, the light modulating elements being aligned in a light-axis direction so as to correspond to the respective pixels,
wherein color tones in the respective pixels with respect to an image printed on printing paper are controlled based upon the subtractive color process by allowing the respective light modulating elements to control the transmission and interruption of light rays having respectively specific wavelength bands.
With the above-mentioned arrangement, the exposing means has an arrangement in which a plurality of light modulating elements are aligned in the light axis direction so as to correspond to the respective pixels, and color tones in the respective pixels with respect to an image printed on printing paper are controlled based upon the subtractive color process by allowing the respective light modulating elements to control the transmission and interruption of light rays having respectively specific wavelength bands; therefore, it is possible to eliminate the need for constructions such as a composition prism for composing light rays having respective color components. Thus, it becomes possible to simplify the structure, and consequently to reduce production costs and material costs.
Moreover, since the light modulating elements are placed in parallel with each other in the light axis direction, it is possible to make the size of the exposing means itself comparatively smaller. Therefore, it becomes possible to make the apparatus itself smaller, and also to increase the degree of freedom in arranging the constituent elements.
Furthermore, the light modulating elements are aligned in the light axis direction in association with the respective pixels, so that light rays having the respective wavelength bands in the respective pixels are directed on the same position on a photosensitive material. Therefore, it is possible to eliminate the generation of pixel offsets in an image printed on the photosensitive material, and consequently to provide high-quality images.
Here, since the light rays having the respective wavelength bands are simultaneously directed onto the photosensitive material, the exposing speed can be increased, for example, as compared with an arrangement in which light rays having the respective wavelength bands are exposed in series with each other.
Moreover, the photograph processing apparatus of the present invention is provided with:
a printing device for carrying out a digital exposing process on a photosensitive material based upon image data;
a developing section for developing the photosensitive material that has been subjected to the printing process by the printing device by using a developer; and
a drying section for drying the photosensitive material that has been subjected to the developing process by the developing section,
wherein the printing device is provided with:
a light source; and
an exposing means for modulating light from the light source for each pixel and for directing the resulting light to a photosensitive material, the exposing means being provided with a plurality of light modulating elements which control the transmission and interruption of light rays having respectively different specific wavelength bands and which transmit light rays having the other wavelength bands, the light modulating elements being aligned in a light-axis direction so as to correspond to the respective pixels,
wherein color tones in the respective pixels with respect to an image printed on printing paper are controlled based upon the subtractive color process by allowing the respective light modulating elements to control the transmission and interruption of light rays having respectively specific wavelength bands.
With the above-mentioned arrangement, first, in the printing device, the exposing means has an arrangement in which a plurality of light modulating elements are aligned in the light axis direction so as to correspond to the respective pixels, and color tones in the respective pixels with respect to an image printed on printing paper are controlled based upon the subtractive color process by allowing the respective light modulating elements to control the transmission and interruption of light rays having respectively specific wavelength bands; therefore, it is possible to eliminate the need for constructions such as a composition prism for composing light rays having respective color components. Thus, it becomes possible to simplify the structure, and consequently to reduce production costs and material costs.
Here, since the light modulating elements are placed in parallel with each other in the light axis direction, it is possible to make the size of the exposing means itself comparatively smaller. Therefore, it becomes possible to make the apparatus itself smaller, and also to increase the degree of freedom in arranging the constituent elements.
Moreover, the light modulating elements are aligned in the light axis direction in association with the respective pixels, so that light rays having the respective wavelength bands in the respective pixels are directed on the same position on a photosensitive material. Therefore, it is possible to eliminate the generation of pixel offsets in an image printed on the photosensitive material, and consequently to provide high-quality images.
Here, since the light rays having the respective wavelength bands are simultaneously directed onto the photosensitive material, the exposing speed can be increased, for example, as compared with an arrangement in which light rays having the respective wavelength bands are exposed in series with each other.
Moreover, since the printing device, the developing section and the drying section are installed as described above, the exposing, developing and drying processes of the photosensitive material are continuously carried out under one unified control. Consequently, it is possible to continuously print a large number of photographs without giving any operational burden to the user.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.